Treatment systems for removing heat from subcutaneous lipid-rich cells

ABSTRACT

The present invention relates to methods for use in the selective disruption of lipid-rich cells by controlled cooling. The present invention further relates to a device for use in carrying out the methods for selective disruption of lipid-rich cells by controlled cooling.

RELATED APPLICATIONS/PATENTS & INCORPORATION BY REFERENCE

This application is a divisional under 35 U.S.C. §121 of U.S. patentapplication Ser. No. 11/434,478, filed on May 15, 2006, which is adivisional under 35 U.S.C. §121 of U.S. patent application Ser. No.10/391,221, filed Mar. 17, 2003 and issued as U.S. Pat. No. 7,367,341 onMay 6, 2008, which claims priority under 35 U.S.C. §119(e) to U.S.Provisional Patent Application Ser. No. 60/365,662, filed on Mar. 15,2002. The contents of each of these patent applications are herebyexpressly incorporated by reference herein.

Each of the applications and patents cited in this text, as well as eachdocument or reference cited in each of the applications and patents(including during the prosecution of each issued patent; “applicationcited documents”), and each of the PCT and foreign applications orpatents corresponding to and/or claiming priority from any of theseapplications and patents, and each of the documents cited or referencedin each of the application cited documents, are hereby expresslyincorporated herein by reference. More generally, documents orreferences are cited in this text, either in a Reference List before theclaims, or in the text itself; and, each of these documents orreferences (“herein-cited references”), as well as each document orreference cited in each of the herein-cited references (including anymanufacturer's specifications, instructions, etc.), is hereby expresslyincorporated herein by reference.

STATEMENT OF RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH

Not applicable.

FIELD OF THE INVENTION

The present invention relates to methods for use in the selectivedisruption of lipid-rich cells by controlled cooling. The presentinvention further relates to a device for use in carrying out themethods for selective disruption of lipid-rich cells by controlledcooling. Other aspects of the invention are described in or are obviousfrom the following disclosure (and within the ambit of the invention).

BACKGROUND

The subcutaneous fatty tissue of newborns is unusually sensitive to thecold. In newborns, the intracellular lipid content of the subcutaneousfat cells, or “adipocytes,” comprises increased ratios of highlysaturated triglycerides. Even moderately cold temperatures can adverselyaffect cells having a highly saturated lipid content, rendering newbornsubcutaneous fatty tissue vulnerable to adipocyte necrosis followingexposure to the cold. Hypothermia of subcutaneous fatty tissue canresult in associated inflammation of the dermis and/or epidermis. Forexample, disorders of cold panniculitis in newborns are known to producepainful skin lesions.

As newborns mature, the ratio of saturated to unsaturated fatty acidsamong intracellular triglycerides of adipocytes gradually decreases.Having a higher content of unsaturated fatty acids is more protectiveagainst the cold, and the occurrence of cold panniculitis in infantsgradually subsides. For detailed reviews on the subject of coldpanniculitis, see Epstein et al. (1970) New England J. of Med.282(17):966-67; Duncan et al. (1966) Arch. Derm. 94:722-724; Kellum etal. (1968) Arch. Derm. 97:372-380; Moschella, Samuel L. and Hurley,Harry J. (1985) Diseases of the Corium and Subcutaneous Tissue. InDermatology (W.B. Saunders Company):1169-1181; John C Maize (1998)Panniculitis In Cutaneous Pathology (Churchill Livingstone): 327-344;Bondei, Edward E. and Lazarus, Gerald S. (1993) Disorders ofSubcutaneous Fat (Cold Panniculitis). In Dermatology in General Medicine(McGraw-Hill, Inc.): 1333-1334

In adults, the intracellular lipid content varies among cell types.Dermal and epidermal cells, for instance, are relatively low inunsaturated fatty acids compared to the underlying adipocytes that formthe subcutaneous fatty tissue. For a detailed review of the compositionof fatty tissue in mammals, see Renold, Albert E. and Cahill, Jr.,George F. (1965) Adipose Tissue. In Handbook of Physiology (AmericanPhysiology Society):170-176. As a result, the different cell types,e.g., lipid-rich and non-lipid-rich cells, have varying degrees ofsusceptibility to the cold. In general, non-lipid-rich cells canwithstand colder temperatures than lipid-rich cells.

It would be highly desirable to selectively and non-invasively damageadipocytes of the subcutaneous fatty tissue without causing injury tothe surrounding dermal and epidermal tissue. Both health and cosmeticbenefits are known to result from reduction of fatty tissue, however,current methods, such as liposuction, involve invasive procedures withpotentially life threatening risks (e.g., excessive bleeding, pain,septic shock, infection and swelling).

Current methods for non-invasive removal of subcutaneous fatty tissueinclude the use of radiant energy and cooling solutions. U.S. Pat. Nos.5,143,063, 5,507,790 and 5,769,879 describe methods for using radiantenergy to reduce subcutaneous fatty tissue, however, the applied energylevels are difficult to control and often there is collateral damage tothe dermis and/or epidermis. Cooling solutions proposed by InternationalPublication No. WO 00/44346 do not stabilize skin surface temperaturesand therefore, also fail to adequately protect against collateral damageto the dermis and/or epidermis.

A previous study conducted in Guinea Pigs described the removal ofsubcutaneous fatty tissue by cryo-damage. Burge, S. and Dawber, R.(1990) Cryobiology 27:153-163. However this result was achieved usingrelatively aggressive cooling modalities (e.g., liquid nitrogen), whichinduced epidermal damage. Ideally, removal of subcutaneous fatty tissueby cooling would not cause associated damage to the epidermis.

Temperature controlled methods and devices for selectively damaginglipid-rich cells (e.g., adipocytes comprising the subcutaneous fattytissue) without causing injury to non lipid-rich cells (e.g., dermisand/or epidermis) were heretofore unknown.

SUMMARY

It has now been shown that adipose tissue comprising lipid-rich cellscan be selectively disrupted without causing injury to the surroundingnon lipid-rich tissue (e.g., dermal and epidermal tissue) by controllingthe temperature and/or pressure applied to the respective tissues.

In one aspect, the invention relates to a cooling method for selectivedisruption of lipid-rich cells in a non-infant human subject comprisingapplying a cooling element proximal to the subject's skin to create atemperature gradient within a local region sufficient to selectivelydisrupt and thereby reduce the lipid-rich cells of said region, and,concurrently therewith maintain the subject's skin at a temperaturewherein non lipid-rich cells proximate to the cooling element are notdisrupted.

In one embodiment, the invention relates to a method for treating aregion of a subject's body to achieve a desired reduction insubcutaneous adipose tissue, comprising a) applying a cooling elementproximal to the subject's skin in the region where subcutaneous adiposetissue reduction is desired to create a temperature gradient within saidregion sufficient to selectively disrupt lipid-rich cells therein, and,simultaneously therewith maintain the subject's skin at a temperaturewherein non lipid-rich cells proximate to the cooling element are notdisrupted; b) repeating the application of the cooling element to thesubject's skin of step (a) a plurality of times until the desiredreduction in subcutaneous adipose tissue has been achieved.

In another aspect, the invention relates to a device for selectivelydisrupting lipid-rich cells in a non-infant human subject by coolingcomprising: means for creating a temperature gradient within a localregion of the subject's skin to selectively disrupt and thereby reducelipid-rich cells of the region, while, concurrently therewith,maintaining the subject's skin at a temperature whereby non lipid-richcells are not disrupted.

In one embodiment, the invention relates to an apparatus for locallyreducing lipid-rich cells, comprising a treatment device operable toreceive a cooling agent; a cooling agent source connected to thetreatment device for supplying said cooling agent; a control unitcoupled to the treatment device and the cooling agent source forcontrolling a cooling temperature of said cooling agent, wherein saidtreatment device exposes target tissue to said cooling agent, whichselectively induces damage to lipid-rich cells at said target tissue.

In another embodiment, the invention further relates to an apparatus forlocally reducing lipid-rich cells, comprising a means for setting acooling agent to a predetermined temperature; and a means for applyingsaid cooling agent to target tissue, whereby the cooling agentselectively induces damage to lipid-rich cells at said target tissue.

In this disclosure, “comprises,” “comprising,” “containing” and “having”and the like can have the meaning ascribed to them in U.S. Patent lawand can mean “includes,” “including,” and the like; “consistingessentially of” or “consists essentially” likewise has the meaningascribed in U.S. Patent law and the term is open-ended, allowing for thepresence of more than that which is recited so long as basic or novelcharacteristics of that which is recited is not changed by the presenceof more than that which is recited, but excludes prior art embodiments.

These and other objects and embodiments are described in or are obviousfrom and within the scope of the invention, from the following DetailedDescription.

DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a treatment system.

FIG. 1B depicts a diagram illustrating a configuration of control unit.

FIG. 1C depicts a diagram showing cooling/heating element.

FIG. 1D illustrates a flat cooling treatment system with a probecontroller.

FIG. 2A illustrates a treatment system for cooling lipid-rich cellswithin a skin fold. FIG. 2B illustrates a treatment system for coolinglipid-rich cells within a skin fold with a probe controller.

FIGS. 3A and 3B illustrate a treatment system that includes a suctionunit.

FIG. 4 illustrates a treatment system that is combined with suctionsystem to provide treatment of an isolated area.

FIGS. 5A and 5B illustrate a treatment system which can enclosecircumferentially a target tissue mass.

FIG. 6 depicts an image of the skin surface showing indentation after 17days at some areas matching cold exposure sites.

FIG. 7 depicts histology of the subcutaneous adipose tissue 17 daysafter cold exposure (Pig II, Site E). FIG. 7A shows the lowmagnification view and FIG. 7B shows the high magnification view.

FIGS. 8A and 8B depict Site C; FIGS. 8C and 8D depict Site E; and FIGS.8E and 8F depict Site F; each of which show histology of thesubcutaneous adipose tissue 17 days after cold exposure (Pig II, Site C,E and F).

FIG. 9 depicts an image of the device used to administer cooling to PigIII.

FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, and 10J depicttemperature plots of the exposure sites 1, 2, 7, 11, 12, 13, 14, 15, 16and 18 of Pig III in various tissue depths.

FIG. 11 depicts an ultrasound image of test Site 11, 3.5 months afterexposure.

FIGS. 12A and 12B depict histology of test Site 8, 6 days afterexposure.

FIGS. 12C and 12D depict histology of test Site 9 (control).

FIGS. 13A, 13B, 13C, 13D, and 13E depict macroscopic sections throughthe center of test Sites 1, 3, 11, 12 and 18, 3.5 months after exposure.

DETAILED DESCRIPTION

The present invention relates to a method for locally reducing adiposetissue comprising applying a cooling element to a subject at atemperature sufficient to selectively disrupt lipid-rich cells, whereinthe temperature does not produce unwanted effects in non lipid-richcells. Preferably, the cooling element is coupled to or contains acooling agent.

In one aspect, the invention relates to a cooling method for selectivedisruption of lipid-rich cells in a non-infant human subject comprisingapplying a cooling element proximal to the subject's skin to create atemperature gradient within a local region sufficient to selectivelydisrupt and thereby reduce the lipid-rich cells of said region, and,concurrently therewith maintain the subject's skin at a temperaturewherein non lipid-rich cells proximate to the cooling element are notdisrupted.

In one embodiment, the invention relates to a method for treating aregion of a subject's body to achieve a desired reduction insubcutaneous adipose tissue, comprising a) applying a cooling elementproximal to the subject's skin in the region where subcutaneous adiposetissue reduction is desired to create a temperature gradient within saidregion sufficient to selectively disrupt lipid-rich cells therein, and,simultaneously therewith maintain the subject's skin at a temperaturewherein non lipid-rich cells proximate to the cooling element are notdisrupted; b) repeating the application of the cooling element to thesubject's skin of step (a) a plurality of times until the desiredreduction in subcutaneous adipose tissue has been achieved.

Cooling elements of the present invention can contain cooling agents inthe form of a solid, liquid or gas. Solid cooling agents can comprise,for example thermal conductive materials, such as metals, metal plates,glasses, gels and ice or ice slurries. Liquid cooling agents cancomprise, for example, saline, glycerol, alcohol, or water/alcoholmixtures. Where the cooling element includes a circulating coolingagent, preferably the temperature of the cooling agent is constant.Salts can be combined with liquid mixtures to obtain desiredtemperatures. Gasses can include, for example, cold air or liquidnitrogen.

In one embodiment, cooling elements can be applied such that directcontact is made with a subject, via either the agent or the element. Inanother embodiment, direct contact is made via the agent alone. In yetanother embodiment, no direct contact is made via either the agent orthe element; cooling is carried out by proximal positioning of thecooling element and/or agent.

Preferably, the temperature of the cooling agent is less than about 37°C., but not less than −196° C. (i.e, the temperature of liquidnitrogen).

Preferably, the temperature range of the administered cooling element isbetween about 40° C. and −15° C., even more preferably between 4° C. and−10° C. if the cooling agent is a liquid or a solid. Generally, thecooling element is preferably maintained at an average temperature ofbetween about −15° C. and about 35° C., 30° C., 25° C., 20° C., 15° C.,10° C., or 5° C.; about −10° C. and about 35° C., 30° C., 25° C., 20°C., 15° C., 10° C., or 5° C.; about −15° C. and about 20° C., 15° C.,10° C., or 5° C.

The cooling element and/or agent can be applied for up to two hours.Preferably, the cooling element is applied for between 1 to 30 minutes.The cooling element can be applied for at least one hundred milliseconds(e.g., shorter durations are envisioned, for instance, with sprays). Forexample, liquid nitrogen can be applied in very short intervals (e.g.,about 1 second), repeatedly (e.g., about 10-100 times) and betweenapplications, a temperature that does not cause epidermal damage ismaintained (e.g., about 0° C. to −10° C., depending on the length ofexposure). In a gentle cooling regime, for example, the liquid nitrogencan be sprayed from a distance (e.g., from about 10 to 30 cm) whereinsome portion of the liquid nitrogen droplets evaporate during thespraying and/or mix with ambient air.

Cooling elements and/or agents of the present invention are applied, forexample, to the skin surface through either direct or indirect contact.A subject's skin comprises the epidermis, dermis or a combinationthereof. The cooling element and/or agent is a non-toxic cooling agentwhen applied directly to the skin surface.

The cooling element and/or agent can be applied more than once, forexample, in repetitious cycles. The cooling agent can be applied in apulsed or continuous manner. The cooling element and/or agent can beapplied by all conventional methods known in the art, including topicalapplication by spray if in liquid form, gas or particulate solidmaterial. Preferably, application is by external means, however, coolingelements and/or agents of the present invention can also be appliedsubcutaneously by injection or other conventional means. For example,the cooling agent can be applied directly to the subcutaneous tissue andthen either removed after contact or left in the subcutaneous tissue toachieve thermal equilibration and therefore cooling of the lipid-richtissue (e.g., subcutaneous injection of a liquid cooling agent or ofsmall cooling particles, such as pellets or microbeads).

Preferably, methods of the present invention are non-invasive (e.g.,superficial, laparoscopic or topical procedures not requiring invasivesurgical techniques).

The cooling element and/or agent can be applied to one defined area ormultiple areas. Spatial distribution of the cooling element and/or agentcan be controlled as needed. Generally, the dimension of the surfacearea (e.g., where the cooling agent is in contact with the skin) shouldbe at least three times the depth of subcutaneous fatty tissue that istargeted for cooling. Preferably, the minimum diameter of the surfacearea is at least 1 cm². Even more preferably, the diameter of thesurface area is between 3 to 20 cm². Determination of the optimalsurface area will require routine variation of several parameters. Forexample, larger surface areas, such as those over 3500 cm², can becooled according to the methods of the present invention if hypothermiais prevented by additional means. Hypothermia can be prevented bycompensating for the heat transfer away from the body at other sites(e.g., applying warm water at one or more additional sites). Multiplecooling elements and/or agents can be employed, for example, incontacting larger surface areas (e.g., greater than 3500 cm²).

The cooling element and/or agent can follow the contour of the area towhich it is applied. For example, a flexible apparatus can be used tofollow the contour of the surface area where cooling is applied. Theapparatus can also modify the shape of the contacted surface such thatthe surface is contoured around or within the cooling agent or theapparatus containing the cooling agent upon contact. The cooling elementand/or agent can contact more than one surface at once, for example,when the surface is folded and contacted on either side by the coolingelement and/or agent. Preferably, a skin fold is contacted on both sidesby the cooling element and/or agent to increase the efficiency ofcooling.

Preferably, the solid cooling element and/or agent is shaped to enhancethermodynamic heat exchange (“thermal exchange”) at the contactedsurface (e.g., skin surface). In order to enhance conduction, a liquidcan be used at the interface between the solid cooling agent and thecontacted surface.

Where necessary, application of the cooling element and/or agent can becoupled with use of a pain management agent, such as an anesthetic oranalgesic (cooling alone has analgesic properties, thus use ofadditional pain management agents is optional). Local anesthetics, forexample, can be topically applied at the point of contact either before,after or during application of the cooling agent. Where necessary,systemic administration of the anesthetic can be provided throughconventional methods, such as injection or oral administration. Thetemperature of the cooling agent can be changed during the treatment,for example, so that the cooling rate is decreased in order to provide atreatment causing less discomfort. In addition, methods of the presentinvention can be performed in combination with other fat reductionprocedures known in the art, such as liposuction.

Preferably, lipid-rich cells of the present invention are adipocyteswithin subcutaneous fatty tissue or cellulite. Thus, lipid-rich cellscomprising the subcutaneous adipose tissue are targeted for disruptionby methods of the present invention. In addition, it is within the ambitof the invention to target disruption of lipid-rich cells comprisingadventicia surrounding organs or other internal anatomical structures.

The intracellular lipids of adipocytes are confined within theparaplasmatic vacuole. There are univacular and plurivacular adipocyteswithin the subcutaneous fatty tissue. Most are univacular, and greaterthan about 100 um in diameter. This size can increase dramatically inobese subjects due to an increase in intracellular lipid content.

Preferably, lipid-rich cells of the present invention have a totalintracellular lipid content of between 20-99%. Preferably, lipid-richcells of the present invention have an intracellular lipid contentcomprised of about 20-50% saturated triglycerides, and even morepreferably about 30-40% saturated triglycerides. Intracellulartriglycerides include, but are not limited to, saturated fatty acidse.g., myristic, palmitic and stearic acid; monounsaturated fatty acids,e.g., palmitoleic and oleic acid; and polyunsaturated fatty acids e.g.,linoleic and linolenic acid.

Preferably, lipid-rich cells of the present invention are located withinsubcutaneous adipose tissue. The saturated fatty acid composition ofsubcutaneous adipose tissue varies at different anatomical positions inthe human body. For example, human subcutaneous adipose tissue in theabdomen can have the following composition of saturated fatty acids:myristic (2.6%), palmitic (23.8%), palmitoleic (4.9%), stearic (6.5%),oleic (45.6%), linoleic (15.4%) and linolenic acid (0.6%). Thesubcutaneous adipose tissue of the abdominal area can comprise about 35%saturated fatty acids. This is comparatively higher than the buttockarea, which can comprise about 32% saturated fatty acids. At roomtemperature, saturated fatty acids of the abdominal area are in asemisolid state as a result of the higher fatty acid content. Thebuttock area is not similarly affected. Malcom G. et al., (1989) Am. J.Clin. Nutr. 50(2):288-91. One skilled in the art can modify temperatureranges or application times as necessary to account for anatomicaldifferences in the response to cooling methods of the present invention.

Preferably, non lipid-rich cells of the present invention have a totalintracellular lipid content of less than 20%, and/or are not disruptedby cooling methods of the present invention. Preferably, non lipid-richcells of the present invention include cells having an intracellularlipid content comprising less than about 20% highly saturatedtriglycerides, even more preferably less than about 7-10% highlysaturated triglycerides. Non lipid-rich cells include, but are notlimited to, those surrounding the subcutaneous fatty tissue, such ascells of the vasculature, peripheral nervous system, epidermis (e.g.,melanocytes) and dermis (e.g., fibrocytes).

Damage to the dermis and/or epidermis that is avoided by the methods ofthe present invention can involve, for example, inflammation,irritation, swelling, formation of lesions and hyper or hypopigmentationof melanocytes.

Without being bound by theory, it is believed that selective disruptionof lipid-rich cells results from localized crystallization of highlysaturated fatty acids upon cooling at temperatures that do not inducecrystallization of highly saturated fatty acids in non lipid-rich cells.The crystals rupture the bilayer membrane of lipid-rich cells, causingnecrosis. Thus, damage of non lipid-rich cells, such as dermal cells, isavoided at temperatures that induce crystal formation in lipid-richcells. It is also believed that cooling induces lipolysis (e.g.,metabolism) of lipid-rich cells, further enhancing the reduction insubcutaneous adipose tissue. Lipolysis may be enhanced by local coldexposure inducing stimulation of the sympathetic nervous system.

In one embodiment, the temperature of the lipid-rich cells is not lessthan about −10° C. Preferably, the temperature of the lipid-rich cellsis between −10° C. and 37° C. More preferably, the temperature of thelipid-rich cells is between −4° C. and 20° C. Even more preferably, thetemperature of the lipid-rich cells is between −2° C. and 15° C.Preferably, the lipid-rich cells are cooled to less than 37° C., for upto two hours. Generally, the lipid-rich cells are preferably maintainedat an average temperature of between about −10° C. and about 37° C., 35,30° C., 25° C., 20° C., 15° C., 10° C., or 4° C.; about −4° C. and about35° C., 30° C., 25° C., 20° C., 15° C., 10° C., or 4° C.; about −2° C.and about 35, 30° C., 25° C., 20° C., 15° C., 10° C., or 5° C.

In yet another embodiment, the temperature range of the lipid-rich cellsoscillates between 37° C. and −10° C. Methods of pulse cooling followedby brief periods of warming can be used to minimize collateral damage tonon lipid-rich cells. More preferably, the temperature range of thelipid-rich cells oscillates between −8° C. and 33° C. Even morepreferably, the temperature range of the lipid-rich cells oscillatesbetween −2° C. and 15° C. The temporal profile of the cooling of theskin can be performed in one continuous cooling act or in multiplecooling cycles or actually a combination of cooling with active heatingcycles.

Cooling methods of the present invention advantageously eliminateunwanted effects in the epidermis. In one embodiment, the temperature ofthe epidermis is not less than about −15° C. Preferably, the temperatureof the epidermis is between about −10° C. and 35° C. More preferably,the temperature of the epidermis is between about −5° C. and 10° C. Evenmore preferably, the temperature of the epidermis is between about −5°C. and 5° C.

Cooling methods of the present invention advantageously eliminateunwanted effects in the dermis. In one embodiment, the temperature ofthe dermis is not less than about −15° C. Preferably, the temperature ofthe dermis is between about −10° C. and 20° C. More preferably, thetemperature of the dermis is between about −8° C. and 15° C. Even morepreferably, the temperature of the dermis is between about −5° C. and10° C. In a preferred embodiment, the lipid-rich cells are cooled toabout −5° C. to 5° C. for up to two hours and the dermal and epidermalcells maintain an average temperature of about 0° C. In a most preferredembodiment, the lipid-rich cells are cooled to about −5° C. to 15° C.for times ranging from about a minute, up to about two hours.

Methods of the present invention can be applied in short intervals(e.g., 1 minute, 5 minute, 15 minute, 30 minute and 60 minute timeintervals) or long intervals (e.g., 12 hour and 24 hour time intervals).Preferably intervals are between 5 and 20 minutes. Heat can optionallybe applied between intervals of cooling.

Feedback mechanisms can be employed to monitor and control temperaturesin the skin (i.e., dermis, epidermis or a combination thereof)subcutaneous adipose tissue. A feedback mechanism can monitor thetemperature of a subject's skin to ensure that the temperature thereindoes not fall below a predetermined minimum temperature, for example,about −10° C. to about 30° C. A non-invasive device can be externallyapplied to measure surface temperature at the point of contact and/orthe surrounding region. An invasive device, such as a thermocouple, canbe used to measure internal temperatures.

Feedback mechanisms can include all known in the art to monitortemperature and/or crystal formation. Crystal formation can be measured,for example by ultrasound imaging and acoustical, optical, andmechanical measurements. Mechanical measurements can include, forexample, measurements of tensile strength.

In one embodiment, a multilayer model can be employed to estimatetemperature profiles over time and within different depths. Temperatureprofiles are designed to produce a temperature gradient within thetissue, having a lower temperature at the surface. In a preferredembodiment, temperature profiles are designed to minimize blood flowduring cooling. Feedback mechanisms comprising, for example,thermocouples, ultrasound (e.g., to detect phase changes of thesubcutaneous adipose tissue) or shock wave propagation (e.g.,propagation of a shock wave is altered if a phase transition occurs) canbe employed to achieve optimal temperature gradients.

Substantial cooling of the subcutaneous adipose layer, for example to atarget temperature between about −5° C. and 15° C., by cooling at theskin surface has several requirements. Heat extracted from the skinsurface establishes a temperature gradient within the skin, which inturn cools first the epidermis, dermis, and finally subcutaneous adiposelayers. Dermal blood flow brings heat from the body core to the dermis.Dermal blood flow can therefore severely limit cooling of the deepdermis and subcutaneous adipose. Therefore, it is strongly preferred totemporarily limit or eliminate cutaneous blood flow, for example bylocally applying a pressure to the skin greater than the systolic bloodpressure, while cooling as a treatment to achieve reduction insubcutaneous adipose. A general requirement is that the time of coolingat the skin surface must be long enough to allow heat to flow from thedermis and subcutaneous adipose layers in order to achieve the desiredtemperature for treatment of the same. When the subcutaneous adipose iscooled to a temperature below that for crystallization of its lipids,the latent heat of freezing for these lipids must also be removed, bydiffusion. The skin surface cooling temperature and cooling time can beadjusted to control depth of treatment, for example the anatomical depthto which subcutaneous adipose is affected. Heat diffusion is a passiveprocess, and the body core temperature is nearly always close to 37° C.Therefore, another general requirement is that the skin surfacetemperature during cooling, must be lower than the desired target (e.g.,adipocytes) temperature for treatment of the region, for at least partof the time during which cooling is performed.

When cooling a diameter of skin greater than about 2 cm, and with noblood flow, one-dimensional heat diffusion offers a good approximationfor estimating temperature profiles in skin over time during cooling.Heat diffusion is governed by the general diffusion equation,δT/δt=κδ²T/δz², where T (z,t) is the temperature in skin as a functionof depth z and time t, and κ is the thermal diffusivity, which isapproximately 1.3×10⁻³ cm²s⁻¹ for skin tissue. Solutions and approximatesolutions to the heat diffusion equation have been made for planargeometry of a semi-infinite slab, approximating the situation for skin.When the surface of the skin (z=0) is held at a given lower temperature,a useful approximation is that heat flow from a depth z requires a timeof approximately t≅z² to achieve a temperature difference ½ of theinitial difference, where t is in seconds and z is in millimeters. Thus,z² can be considered an approximate value for a thermal time constant.For example, if the initial skin temperature is 30° C., and ice at 0° C.is placed firmly against the skin surface, it requires about 1 secondfor the temperature at a depth of 1 millimeter, to reach about 15° C.The subcutaneous fat layer typically begins at about z≅3 mm, and extendsfor millimeters up to many centimeters thick. The thermal time constantfor heat transfer from the top of the subcutaneous adipose layer, istherefore about 10 seconds. To achieve substantial cooling ofsubcutaneous adipose, at least several and preferably greater than 10thermal time constants of cooling time are required. Therefore, coolingmust be maintained for about 30-100 seconds at the skin surface, and inthe absence of dermal blood flow, for the temperature of the topmostportion of subcutaneous adipose to approach that of the cooled skinsurface. The latent heat of crystallization for lipids, mentioned above,must also be removed when the fat temperature drops below that forcrystallization. Therefore in general, cooling times over 1 minute aredesired, and cooling times greater than about 1 minute can be used toadjust the depth of adipocytes affected, for times up to more than anhour.

Accordingly, in yet another embodiment, the dermis is cooled at a ratesufficient to induce vasoconstriction. Blood circulation within thedermis stabilizes the temperature of the dermis close to bodytemperature. In order to cool subcutaneous adipose tissue totemperatures below body temperature, blood flow can be minimized. Fastcooling of the epidermal surface can achieve reflectory vasoconstrictionthat limits blood circulation in an appropriate way.

In yet another embodiment, a vasoconstrictive drug is administered toinduce vasoconstriction. Vasoconstrictive drugs, for example, can betopically applied at the point of contact either before, after or duringapplication of the cooling agent. Where necessary, systemicadministration of the vasoconstrictive drug can be provided throughconventional methods, such as injection or oral administration. Thevasoconstrictive drug can be any known in the art. Preferably, thevasoconstrictive drug is EMLA cream or epinephrine.

In yet another embodiment, pressure is applied to a surface, either atthe point of contact with the cooling agent or in proximity thereto,such that lateral blood flow is limited. Pressure can be applied, forexample, to a skin surface by compressing the skin surface into a skinfold comprising single or multiple folds. Pressure can also be byapplying a vacuum either at the point of contact with the cooling agentor in proximity thereto.

Without being bound by theory, it is believed that the rate of formationof crystals in lipid-rich cells can be altered by the application ofpressure during the cooling process. Sudden crystallization, rather thana slow accumulation of crystals, would cause greater damage to thelipid-rich cells. It is also believed that the application of pressurecan force the movement of the crystals within the lipid-rich cells,enhancing the damage to the bilayer membrane. Furthermore, differentcompartments of the subcutaneous adipose tissue have differentviscosities. In general, the viscosity is enhanced at coldertemperatures (e.g., those particularly close to the point of phasechange). Because the phase change for lipid-rich cells occurs at highertemperatures than non lipid-rich cells, non-uniform tension lines formwithin the subcutaneous adipose tissue upon the application of pressure.It is believed that pronounced damage occurs within these tension lines.

In yet another aspect, the temperature of the dermis and/or epidermisoscillates between 35° C. and −15° C. More preferably, the temperatureof the dermis and/or epidermis oscillates between −10° C. and 10° C.Even more preferably, the temperature of the dermis and/or epidermisoscillates between −8° C. and 8° C. Oscillating temperatures at the skinsurface can provide intermittent warming to counteract potential sideeffects of the cooling process (e.g., crystal formation in the dermal orepidermal cells).

In yet another aspect, application of the cooling agent is coupled withthe application of electric or acoustic fields, either constant oroscillating in time, localized in the dermis and/or epidermis to reduceor eliminate crystal formation therein.

FIG. 1A illustrates a treatment system 100 for cooling a target area inaccordance with an embodiment of the invention. As shown in FIG. 1A,treatment system 100 may include a control unit 105 and a treatment unit107, which may include a cooling/heating element 110 and a treatmentinterface 115.

Control unit 105 may include a power supply, for example, control unitmay be coupled to a power source, for supplying power to treatment unit107. Control unit 105 can also include a computing device having controlhardware and/or software for controlling, based on inputted propertiesand/or parameters, cooling/heating element 110 and treatment interface115. Treatment interface 115 can include a detector 120.

FIG. 1B is a diagram illustrating a configuration of control unit 105 inaccordance with an embodiment of the invention. As shown in FIG. 1B,control unit 105 can comprise a computing device 125, which can be ageneral purpose computer (such as a PC), workstation, mainframe computersystem, and so forth. Computing device 125 can include a processordevice (or central processing unit “CPU”) 130, a memory device 135, astorage device 140, a user interface 145, a system bus 150, and acommunication interface 155. CPU 130 can be any type of processingdevice for carrying out instructions, processing data, and so forth.Memory device 135 can be any type of memory device including any one ormore of random access memory (“RAM”), read-only memory (“ROM”), Flashmemory, Electrically Erasable Programmable Read Only Memory (“EEPROM”),and so forth. Storage device 140 can be any data storage device forreading/writing from/to any removable and/or integrated optical,magnetic, and/or optical-magneto storage medium, and the like (e.g., ahard disk, a compact disc-read-only memory “CD-ROM”, CD-ReWritable“CD-RW”, Digital Versatile Disc-ROM “DVD-ROM”, DVD-RW, and so forth).Storage device 140 can also include a controller/interface (not shown)for connecting to system bus 150. Thus, memory device 135 and storagedevice 140 are suitable for storing data as well as instructions forprogrammed processes for execution on CPU 130. User interface 145 mayinclude a touch screen, control panel, keyboard, keypad, display or anyother type of interface, which can be connected to system bus 150through a corresponding input/output device interface/adapter (notshown). Communication interface 155 may be adapted to communicate withany type of external device, including treatment unit 107. Communicationinterface 155 may further be adapted to communicate with any system ornetwork (not shown), such as one or more computing devices on a localarea network (“LAN”), wide area network (“WAN”), the internet, and soforth. Interface 155 may be connected directly to system bus 150, or canbe connected through a suitable interface (not shown). Control unit 105can, thus, provide for executing processes, by itself and/or incooperation with one or more additional devices, that may includealgorithms for controlling treatment unit 107 in accordance with thepresent invention. Control unit 105 may be programmed or instructed toperform these processes according to any communication protocol,programming language on any platform. Thus, the processes may beembodied in data as well as instructions stored in memory device 135and/or storage device 140 or received at interface 155 and/or userinterface 145 for execution on CPU 130.

Referring back to FIG. 1A, treatment unit 107 may be a handheld device,an automated apparatus, and the like. Cooling/heating element 110 caninclude any type of cooling/heating component, such as a thermoelectriccooler and the like.

FIG. 1C is a diagram showing cooling/heating element 110 in accordancewith an embodiment with the present invention. As shown in FIG. 1C,cooling/heating element 110 can include a network of passages where acooling/heating fluid flows through. The passages may be formed by anyheat conducting tubing and the like. The cooling/heating fluid can bedirected into element 110 through an input 175 and expelled through anoutput 180. The cooling/heating fluid may be any fluid having acontrolled temperature, such as cooled air/gas or liquid. For example, asaltwater or acetone bath that is cooled using ice or frozen carbondioxide may be used as a source of cooled liquid pumped through element110. A circulating system may, thus, be formed where fluid expelled atoutput 180 is re-cooled at the fluid source and re-directed into input175. The temperature of the fluid source and/or element 110, which mayinclude the rate at which cooling fluid is pumped through element 110,can be monitored and controlled by control unit 105. Thus, thetemperature of cooling/heating element 110 can be controlled orprogrammed using control unit 105. As further shown in FIG. 1C, therecan be a temperature difference, ΔT, between regions of element 110. Forexample, heat from the target tissue may be transferred to the coolingfluid during treatment causing fluid near output 180 to have a highertemperature than the cooling fluid near input 175. Such ΔT may bereduced by reducing the size of element 110. In accordance with anembodiment of the invention, the configuration of the passages inelement 110 and the corresponding application of element 110 to targettissue can account for any difference in temperature needed for treatingvarious tissue targets. For example, the region of element 110 near exit180 can be applied to treatment areas requiring a higher treatmenttemperature, and so forth. The passages of element 110 can, thus, beconfigured in accordance with the size, shape, formation, and so forth,of target tissue that require the various treatment temperatures.Cooling/heating fluid can also be pumped through element 110 in apulsing manner.

Referring back to FIG. 1A, treatment interface 115 can be any type ofinterface between cooling/heating element 110 and the epidermis 160 foreffecting treatment onto the epidermis 160, dermis 165 and fat cells170. For example, treatment interface 115 may include a cooling(conductive) plate, a cooling fluid-filled vessel, a free-formingmembrane (for a complementary interface with an uneven epidermis), aconvex cooling element (for example, as shown in FIG. 3), and the like.Preferably, treatment interface 115 comprises a heat conducting materialthat complements the epidermis 160 for maximum heat transfer betweencooling/heating element 110 and the epidermis 160, dermis 165 and/or fatcells 170. For example, treatment interface 115 can be a fluid-filledvessel or a membrane so that the change in pressure from cooling element110 caused by a pulsing flow of cooling fluid may be transferred to thetarget tissue. Furthermore, treatment interface 115 may simply be achamber where cooling/heating fluid may be applied directly to thetarget tissue (epidermis 160, dermis and fat cells 170), for example byusing a spraying device and the like.

Detector 120 can be a temperature monitor, for example, a thermocouple,a thermistor, and the like. Detector 120 may include any thermocoupletype, including Types T, E, J, K, G, C, D, R, S, B, for monitoringtissue cooling. Detector 120 may also include a thermistor, which cancomprise thermally-sensitive resistors whose resistances change with achange in temperature. The use of thermistors may be particularlyadvantageous because of their sensitivity. In accordance with anembodiment of the invention, a thermistor with a large negativetemperature coefficient of resistance (“NTC”) can be used. Preferably, athermistor used for detector 120 may have a working temperature rangeinclusive of about −15° C. to 40° C. Furthermore, detector 120 caninclude a thermistor with active elements of polymers or ceramics. Aceramic thermistor may be most preferable as these can have the mostreproducible temperature measurements. A thermistor used for detector120 can be encapsulated in a protective material such as glass. Ofcourse, various other temperature-monitoring devices can also be used asdictated by the size, geometry, and temperature resolution desired.Detector 120 can also comprise an electrode which can be used to measurethe electrical resistance of the skin surface area. Ice formation withinsuperficial skin structures like the epidermis or dermis causes anincreased electrical resistance. This effect can be used to monitor iceformation within the dermis. Detector 120 can further consist of acombination of several measurement methods.

Detector 120 can, thus, extract, inter alia, temperature informationfrom the epidermis 160, dermis 165 and/or fat cells 170 as feedback tocontrol unit 105. The detected temperature information can be analyzedby control unit 105 based on inputted properties and/or parameters. Forexample, the temperature of fat cells 170 may be determined bycalculation based on the temperature of the epidermis 160 detected bydetector 120. Thus, treatment system 100 may non-invasively measure thetemperature of fat cells 170. This information may then be used bycontrol unit 105 for continuous feedback control of treatment unit 107,for example, by adjusting the energy/temperature of cooling/heatingelement 110 and treatment interface 115, thus maintaining optimaltreatment temperature of target fat cells 170 while leaving surroundingepidermis 160 and dermis 165 intact. As described above, thecooling/heating element 110 can provide adjustable temperatures in therange of about −10° C. up to 42° C. An automated temperature measurementand control sequence can be repeated to maintain such temperature rangesuntil a procedure is complete.

It is noted that adipose tissue reduction by cooling lipid-rich cellsmay be even more effective when tissue cooling is accompanied byphysical manipulation, for example, massaging, of the target tissue. Inaccordance with an embodiment of the present invention, treatment unit107 can include a tissue massaging device, such as a vibrating deviceand the like. Alternative a piezoelectric transducer can be used withintreatment unit 107 in order to provide mechanical oscillation ormovement of the cooling/heating element 110. Detector 120 can includefeedback devices for detecting changes in skin viscosity to monitor theeffectiveness of treatment and/or to prevent any damage to surroundingtissue. For example, a vibration detecting device can be used to detectany change in the resonant frequency of the target tissue (orsurrounding tissue), which can indicate a change in tissue viscosity,being mechanically moved or vibrated by a vibrating device contained intreatment unit 107.

To further ensure that the epidermis 160 and/or the dermis 165 is notdamaged by cooling treatment, an optical detector/feedback device can beused to monitor the change of optical properties of the epidermis(enhanced scattering if ice formations occur); an electrical feedbackdevice can be used to monitor the change of electric impedance of theepidermis caused by ice formation in the epidermis; and/or an ultrasoundfeedback device may be used for monitoring ice formation (actually toavoid) in the skin. Any such device may include signaling control unit105 to stop or adjust treatment to prevent skin damage.

In accordance with an embodiment of the invention, treatment system 100may include a number of configurations and instruments. Algorithms thatare designed for different types of procedures, configurations and/orinstruments may be included for control unit 105.

As shown in FIG. 1D, treatment system 100 may include a probe controller175 and a probe 180 for minimal invasive temperature measurement of fatcells 170. Advantageously, probe 180 may be capable of measuring a moreaccurate temperature of fat cells 170, thereby improving the control oftreatment unit 107 and the effectiveness of treatment.

It is noted that treatment system 100 may be controlled remotely. Forexample, the link between control unit 105 and treatment unit 107 may bea remote link (wired or wireless) providing control unit 105 remotecontrol over cooling/heating element 110, treatment interface 115, probecontroller 175, and probe 180.

While the above exemplary treatment system 100 is illustrative of thebasic components of a system suitable for use with the presentinvention, the architecture shown should not be considered limitingsince many variations of the hardware configuration are possible withoutdeparting from the present invention.

FIG. 2A illustrates a treatment system 200 for cooling fat cells 170 byfolding the target tissue in accordance with an embodiment of theinvention. As shown in FIG. 2A, treatment system 200 may includecorresponding control units 105 and treatment units 107 on two sidescoupled to a compression unit 205. Compression unit 205 may be adaptedto pull treatment units 107 together, thereby folding (or “pinching”)target tissue (epidermis 160, dermis 165 and fat cells 170) up betweentreatment units 107. The treatment interface 115 of the respectivetreatment units 107 on either side of the target tissue may thus coolfat cells 170 from multiple sides with greater effectiveness, asdescribed above. Detectors 120 can be included to measure and monitorthe temperature of the target tissue. As shown in FIG. 2A, control units105 may be connected to form an integrated system. In accordance with anembodiment of the present invention, the various components of system200 may be controlled using any number of control unit(s).

As described before, physical manipulation of target tissue may improvethe effectiveness of cooling treatment. In accordance with an embodimentof the present invention, compression unit 205 may vary the force withwhich treatment units 107 are pulled together around the target tissue(epidermis 160, dermis 165 and fat cells 170). For example, compressionunit 205 can apply a pulsing force for alternately tightening andloosening the fold (or “pinch”) of the target tissue. Resistance to thetightening can further be monitored for detecting any changes in thecharacteristics (for example, the viscosity) of the target tissue, andthus ensuring the effectiveness and safety of the treatment.

FIG. 2B illustrates system 200 with a probe 180 similar to that ofsystem 100 shown in FIG. 1C for minimal invasive temperature measurementof fat cells 170. As described above, probe 180 may be capable ofmeasuring a more accurate temperature of fat cells 170, therebyimproving the control of treatment unit 107 and the effectiveness oftreatment.

FIGS. 3A and 3B are diagrams showing a treatment system 300 inaccordance with an embodiment of the present invention. As shown in FIG.3A, system 300 may include a suction unit 305, and treatment unit 107may include treatment interface 115 having a curved surface, which forexample forms a dome, for forming and containing a chamber 310 above theepidermis 160. As shown in FIG. 3B, suction unit 305 may be activated todraw the air from chamber 310 such that target tissue (epidermis 160,dermis 165 and fat cells 170) is pulled up into contact with treatmentinterface 115. Advantageously, treatment interface 115 may surroundtarget fat cells 170 for more effective cooling. Treatment interface 115can consist of a solid stiff or flexible material, which is in contactwith the skin or a thermal coupling agent between the skin surface andthe treatment unit. The surface of the interface 115 can also havemultiple openings connected to suction unit 305. The skin is partiallyentered into these multiple openings, which can increase the totalsurface area of the epidermis 160 in thermal contact to the treatmentinterface (e.g., stretching of the skin). Stretching of the skindecreases the thickness of the epidermis and dermis, facilitatingcooling of the fat 170. A number of detector(s) 120 and/or probe(s) 180can be included in treatment system 300 for monitoring tissuetemperature during treatment, as described above with reference to FIGS.1A, 1C, 2A and 2B, detailed description of which will not be repeatedhere.

FIG. 4 illustrates a treatment system 400 in accordance with anembodiment of the invention. As shown in FIG. 4, suction unit 305 can beconnected to a ring opening around treatment interface 115 so that, whenactivated, a suction seal 410 is formed with the epidermis 160 aroundtreatment interface 115. As a result, treatment can be effected attreatment interface 115 to an isolated target tissue area.Advantageously, the subject or body part may be immersed in a warmingbath and the treatment at interface 115 can be unaffected. Consequently,treatment area can be increased while a surrounding warming environmentcan prevent general hypothermia.

FIGS. 5A and 5B are diagrams showing a treatment system 500 inaccordance with an embodiment of the present invention. As shown inFIGS. 5A and 5B, treatment system 500 may form a band (or cylinder)around a target tissue mass 515. Treatment system 500 may comprise anyflexible or rigid material. Cooling/heating fluid can be pumped throughtreatment system 500 via input 175 and output 180, as shown in FIG. 5B.Cooling/heating element 110 can be formed by an internal vessel or anetwork of passages, such as tubing and the like. Heat transfer withtarget tissue mass 515 can be effected via treatment interface 115,which can include any heat conducting material. Treatment system 500 canfurther include a fastening mechanism 510, such as a hook and loopfastener and the like, for fastening and wrapping around tissue mass515. Furthermore, treatment interface 115 can include a flexiblematerial such that the pressure of cooling fluid pumped throughtreatment system 500 can be transferred to the target tissue 515. Forexample, with reference to FIG. 5A, treatment system 500 can applyinward pressure to target tissue mass 515. Target tissue mass 515 can beany section, body part or extremity of a subject. For example, targettissue mass 515 can be an arm, the upper or lower leg, the waist, and soforth, of a subject. The pressure and flow of the cooling fluid insystem 500 can be controlled by control unit 105 to an optimal treatmenttemperature and/or pressure. A tight fit around tissue mass 515 andincreased inward pressure can also allow for the subject to be immersedin a warming bath. As described before, fluid flow can be a pulsingflow.

The present invention is additionally described by way of the followingillustrative, non-limiting Examples, that provide a better understandingof the present invention and of its many advantages

EXAMPLES Example 1 Selective Damage to Fatty Tissue by ControlledCooling In Vivo

Methods of the present invention were carried out on a white, 6 monthold, female, Hanford miniature pig (“Pig I”) and a black, 6 month old,female Yucatan Miniature Pig (“Pig II”). The pigs were anesthetizedusing Telazol/Xylazine (4.4 mg/kg im+2.2 mg/kg im). Inhalant anesthetics(Halothane or Isoflurane (1.5-3.0%) with Oxygen (3.0 L/min)) wasdelivered by mask and filtered with an F-Air canister only if theinjectable anesthetics did not provide enough somatic analgesia. Severaltest sites were marked with micro tattoos by applying India Ink to thecorners of each test sites. After mapping of the test sites coldexposures were performed using a cooling device as described in FIG. 1A.The area of the treatment interface was a flat area of the size of 2×4cm² with a built-in temperature sensor. The interface was in thermalcontact with a thermoelectric chiller, which was electronicallyregulated by a control unit such that the temperature at the surface ofthe interface was kept constant to a pre-set temperature. During thecold exposure the cooling device was applied to the skin with minor tomoderate pressure that did not cause significant mechanical compressionof blood flow. The cooling element was applied to the skin without anymanipulation of the surface profile.

Various combinations of pre-set cooling interface temperatures andexposure times were tested. For some sites a thermo-conductive lotionwas applied between the skin and the cooling interface. Thisthermoconductive lotion consisted mainly of glycerol. Pig I was observedfor 61 days until excision biopsies from all test sites were procuredand the pig was sacrificed. From test Site C there was an additionalpunch biopsy procured at day 2.

The biopsies were processed for routine light microscopy and stainedwith Hematoxylin & Eosin. The indicated temperature is that of theapplied cooling element. Table 1 depicts the parameters of the coolingapplication and the results obtained at various sites in Pig I:

TABLE 1 Site Temperature Time Lotion Results A −6° C. 1 minute + At 61days: No epidermal damage. No dermal damage. No obvious indentation. Noobvious histological alterations. B −6° C. 1 minute − At 61 days: Noepidermal damage. No dermal damage. No obvious indentation. No obvioushistological alterations. C −6° C. 5 minutes + At 61 days: No epidermaldamage. No dermal damage. Indentation due to loss of subcutaneousadipose tissue (1 week to 61 days). Decreased average size of adipocytesat a depth of between about 3-6 mm. Obvious histological damage to theadipose tissue. At 2 days: Tissue inflammation and panniculitis. D −3.5°C.   5 minutes + At 61 days: No epidermal damage. No dermal damage. Noobvious indentation. Borderline histological damage to the adiposetissue. Decreased average size of adipocytes. E Control Normal- nochanges within the epidermis, dermis and subcutaneous adipose tissue.

Pig II was observed for 50 days until excision biopsies from all testsites were procured and the pig was sacrificed. From test Site E anadditional biopsy was procured at day 17. The biopsies were processedfor routine light microscopy and stained with Hematoxylin & Eosin asdescribed above. The indicated temperature is that of the appliedcooling element. Table 2 depicts the parameters of the coolingapplication and the results obtained at various sites in Pig II:

TABLE 2 Site Temperature Time Lotion Results C −6° C. 5 minutes − At 50days: Pronounced indentation (2-3 mm) due to loss of subcutaneousadipose tissue. No epidermal damage. No dermal damage. No pigmentarychanges, however, decreased size of adipocytes and histological damageto adipose tissue. D −8° C. 5 minutes − At 50 days: Pronouncedindentation (2-3 mm) due to loss of subcutaneous adipose tissue. Noepidermal damage. No dermal damage. No pigmentary changes, however,there was damage to the adipocytes to a depth of about 6 mm. Decreasedsize of adipocytes and histological damage to adipose tissue. E −9° C. 5minutes − At 50 days: Pronounced indentation (2-3 mm) due to loss ofsubcutaneous adipose tissue. No epidermal damage. No dermal damage. Nopigmentary changes, however, there was damage to the adipose cells to adepth of about 6 mm. Decreased size of adipocytes and histologicaldamage to adipose tissue. At 17 days: Signs of panniculitis. F −22° C. 5 minutes − At 50 days: Pronounced epidermal damage with pronouncedhypopigmentation. Scar formation with dermal contraction and completeablation of the subcutaneous adipose tissue.

FIG. 6 depicts an image of the skin surface of test Sites D, E and F ofPig II, 17 days after exposure. An indentation that matches the site ofthe cold exposure can be seen at 1, which matches test Site D and 2,which matches test Site E. No abnormal epidermal changes can be seen atthese test sites. At 3, which matches the test Site F, where aggressivecooling methods were applied, damage to the epidermis is pronounced(e.g., loss of pigmentation and a central crust formation).

FIG. 7 depicts histology of test Site E (Pig II), 17 days after coldexposure at −9° C. for 5 minutes, in samples taken from an area belowthe site of cold exposure. FIG. 7A depicts a low power magnification(1.25×) and FIG. 7B depicts a close up with medium power magnification(5×) of the same specimen. The epidermis 701, dermis 702, subcutaneousadipose 703 and muscle layer 704 are shown. The histology reveals signsof lobular and septal panniculits within subcutaneous adipose 703, whichis an inflammation of the adipose tissue. The average size of fat cellsis decreased compared to the sample from the unexposed area. No evidenceof tissue alterations is seen in the epidermis, dermis or muscle layer.

A decrease in subcutaneous adipose tissue was demonstrated by clinicalobservation of indentation within the skin surface at the precise siteof cooling, as well as by histology (Hematoxylin & Eosin staining). FIG.8A, B, C, D, E, and F depicts histology 50 days after exposure with lowpower magnification of 2.5× (FIGS. 8A, 8C and 8E) and medium powermagnification of 5× (FIGS. 8B, 8D and 8F) of test Site C (FIGS. 8A and8B), test Site E (FIGS. 8C and 8D) and test Site F (FIGS. 8E and 8F).The epidermis 801 and dermis 802 is not damaged in test Sites C and Ewhile the more aggressive cooling regime applied to test Site F resultedin damage to the epidermis and dermis (e.g., scar formation andinflammation can be seen). The subcutaneous adipose 803 shows a decreaseof adipocyte size and structural changes (e.g., apparent condensation ofthe fat cell layer with fibrous septae is included in the condensatedfat layer). As a result of the aggressive cooling regime applied to testSite F, almost the entire layer was removed, leaving only some residualfat cell clusters. Thus, where an aggressive cooling regime is applied(test Site F) non-selective and pronounced damage is observed in theepidermis and dermis.

Taken together, the results demonstrate that selective disruption ofsubcutaneous adipose tissue is achieved using cooling methods of thepresent invention without causing damage to the epidermis and dermis.

Measurement of temperature during skin surface cooling at −7° C. appliedwith pressure sufficient to stop skin blood flow, was performed toillustrate the time- and depth-dependence of cooling, in a live pig.Thermocouples inserted at depths of 0, 2, 4, and 8 millimeters were usedto record temperature. Although the conditions of this experiment werenot ideal (the skin cooler did not maintain strictly −7° C. at thesurface), it is clear that cooling of the dermis (2 mm) and fat (4 mm, 8mm) occurred generally as expected (see for example, FIG. 10).

Example 2 Temperature Profile Measurements at Various Tissue Depths

This study was performed using a 6-months old female black, hairlessYucatan Minipig (Sinclair Research Center, Columbia, Mo.). The pig willwas anesthetized using Telazol/Xylazine (4.4 mg/kg im+2.2 mg/kg im).Inhalant anesthetic (Halothane or Isoflurane (1.5-3.0%) with Oxygen (3.0L/min)) was delivered by mask and filtered with an F-Air canister onlyif the injectable anesthetic did not provide enough somatic analgesia.The test sites were marked with micro tattoos by applying India Ink tothe corners of each test site and inserting hypodermic needles into suchtest site corners. The cold exposure was performed with a convex roundcopper plate attached to a heat exchanger, which was chilled by acirculating cooling agent tempered to −7° C. The exposure time rangedbetween 600 to 1200 s. Table 3 depicts the parameters of the coolingapplication and the results obtained at various sites in Pig III. Thecold plate had three central openings of approximately 1 mm in diameterthrough which thermocouples were placed to monitor the temperatureprofile at different depth of the tissue during cold exposure. The coldexposure device, shown in FIG. 9, was firmly held to the test siteduring cold exposure. Cold exposures were performed on two differentexperimental days, one week apart. On the first experimental day thethermocouples were occasionally displaced during the cold exposureleading to a 0.5 mm variability of the thermocouple depth measurement.An additional set of exposures with thermocouples were performed on thesecond experimental day at well-defined depths with minimal to novariability in the depth of the thermocouples. The location of thethermocouples on the first experimental day for test Sites 1, 2, 3, 7,11 and12 was at 2.5, 4.5 and 10 mm depth (+/−0.5 mm). Test Sites 14, 15,16 and 18 were treated on the second experimental day at a thermocoupledepth of 2, 4 and 8 mm, with minimal to no displacement. A certainvariability of the thermocouple depth may still be present due to tissuecompression during the cold exposure. A glycol containing solution wasused to ensure good thermal contact at the skin surface. The pig wasobserved for 3½ months after treatment, until sacrificed and the tissueof the test sites harvested for analysis. Table 3 depicts the parametersof the cooling application and the results obtained at various sites inPig III:

TABLE 3 Relative decrease of Temperature superficial (coolant ExposureTemp_(min) @ Temp_(min) @ Temp_(min) @ Indentation fat layer @ 3½ Siteagent) time Location depth depth depth 3^(1/2) months months 1 −7° C.  5minutes Flank  0° C.@2.5 mm 7° C.@5 mm 24° C.@10 mm + 66% 2 −7° C.  5minutes Flank −2° C.@2.5 mm N/A 21° C.@10 mm + 3 control Flank − 9% 7−7° C. 10 minutes Abdomen −3° C.@2.5 mm 7° C.@5 mm 19° C.@10 mm + 9control Abdomen 11 −7° C. 10 minutes Buttock   N/A N/A 12° C.@10 mm ++79% 12 −7° C. 10 minutes Buttock −4° C.@2.5 mm N/A 13° C.@10 mm + 57% 13−7° C. 10 minutes Buttock   −4° C.@2 mm N/A  7° C.@10 mm + 14 −7° C. 21minutes Buttock   −4° C.@2 mm 3° C.@4 mm  12° C.@8 mm + 15 −7° C. 11minutes Buttock   −4° C.@2 mm 1° C.@4 mm  12° C.@8 mm + 16 −7° C. 10minutes Buttock   −4° C.@2 mm 0° C.@4 mm  14° C.@8 mm ++ 18 −7° C. 15minutes Flank   −3° C.@2 mm N/A  15° C.@8 mm + 66%

The test sites were exposed to the device, set to a coolant temperatureof −7° C. and exposed for 600 to 1200 s. The dermis hardened immediatelyafter the cold exposure, as determined by palpation, and became viscoseas it returned to its normal temperature, approximately a minute afterexposure. There was no epidermal damage or alteration evident byclose-up examination with polarized magnifier lens minutes afterexposure. There was no blister formation and Nikolsky-sign was negative.During the entire survival period there was no gross damage to theepidermis. No crusting, blister or pronounced pigmentary changes wereobserved. Some test sites exhibit a minor increase in epidermalpigmentation. This mild hyperpigmentation could be removed after fewmonths by gentle rubbing of the epidermis.

The temperature measurements of the thermocouples depended on depth,body location, and the pressure with which cooling was applied. Thetemperature plots at different tissue depths during the cold exposureare shown in FIGS. 10 A-J for various test sites and are also summarizedin Table 3. For some test sites, temperature oscillations that might berelated to a nearby blood vessel was observed. Some temperature plotswere not considered due to movements or misplacement of the thermocouple(labeled ‘error’ in Table 3). The temperature within the deep dermis orsuperficial fat layer is within the range of −2° C. to −4° C. Thetemperature within 4-5 mm depth is within the range of about 0° C. to 7°C. depending on variations in contact pressure and anatomical area. Thislocation demonstrated a high variability of the different temperatureplots. The temperature within 8-10 mm depth, which corresponds to adepth within the subcutaneous fat layer had a temperature in the rangeof 7-24° C.

Histology of a control (Site 9) and cold exposed site (Site 8) (−7° C.,600 s) was procured 6 days post exposure and analyzed by adermatopathologist. The following was described at the control and thecold exposed site:

The epidermis of both samples is normal and exhibits basket-wovenstratum corneum with normal thickness, normal rete ridges as compared tothe control. Within the cold exposed site there is a mild perivascular,lymphocytic infiltrate present. However no frank signs of vasculitispresent in both samples.

The subcutaneous fat of the control exhibits the normal morphology. Thesubcutaneous fat of the cold exposed site exhibits clear signs oflobular and septal panniculitis. Most of the adipocytes are surroundedby lymphocytic infiltrate with occasional lipid containing macrophages.The thickness of the subcutaneous septae is increased. Mild vascularchanges however no frank signs of vasculitis. Three and one half monthsafter the cold exposure the pig was sacrificed and tissue at theexposure sites was harvested by full thickness excision, after 20 MHzultrasound imaging was performed through selected test sites. Thein-vivo ultrasound images clearly demonstrated loss of fatty tissue inthe area of treatment by skin cooling vs. the non-cold exposedsurrounding tissue. An in-vivo ultrasound image 3½ months after coldexposure is shown in FIG. 11.

The harvested tissue was cut macroscopically through the test sites andimages were taken from the macroscopic tissue cross-sections. Themacroscopic cross sections of Sites 1, 3, 11, 12 and 18 are shown inFIG. 13 A-E. A decrease of the thickness of the subcutaneous fat layerwas observed for all cold exposed sites vs. the non-cold exposedadjacent fat layer. The macroscopic cross sections matched well with theultrasound images. Two different compartments within the subcutaneousfat could be identified, a superficial fat layer and a deep fat layer.Thickness of the superficial fat layer was dramatically reduced at sitesof cold treatment, while the deep fat layer was not significantlychanged. The percentage of decrease of the superficial fat layer insidethe test area vs. outside is listed for some test sites in Table 3. Achange of the subcutaneous fat layer was observed for cold exposed Sites1, 11, 12 and 18. The average decrease of thickness for the superficialfat layer within the evaluated test sites was 47%. For the unexposedcontrol side, no significant decrease of thickness was found in eitherfat layer.

These examples confirm that it is possible in a pig model to achieveselective tissue damage of the subcutaneous adipose tissue by externalcooling within a specific range of external cooling temperature andexposure time, without significant damage to the epidermis and dermis.Removal of subcutaneous fat was also demonstrated by an obviousindentation at the treated skin surface, which matched exactly with thecooling exposure, and with the measurements of the fat layer in relationto the cold exposure site by ultrasound and macroscopic cross sectionsafter sacrifice. Pronounced histological changes, which were selectiveto the subcutaneous adipose tissue were observed 6 days after coldexposure. Histologically a panniculitis with a decrease in fat cell sizewas observed. There was evidence that the response to the cold can varyfor different sites and that the more superficial fat layer is moreaffected by tissue loss than the deeper fat layer. The results of PigIII however imply that there is enhanced fat removal at the superficialfat layer vs. the deeper layer. The explanation for this is a) thesuperficial fat layer is exposed to colder temperatures because of thegradient and/or b) the deeper fat layer in pigs may be less susceptibleto selective cold damage.

FIG. 9 depicts an image of the device for the cold exposure of Pig III.The cold copper plate 91 is brought in contact with the skin. Thetemperature profile within the skin during cold exposure is measured bythermocouples 92 inserted into the tissue in different depths. Thedevice is spring loaded 93 to provide a pressure during the coldexposure.

FIG. 10 depicts the temperature profile in various depths during thecold exposure of Pig III for different test Sites: 10A (Site 1), 10B(Site 2), 10C (Site 7), 10D (Site 11), 10E (Site 12), 10F (Site 13), 10G(Site 14), 10H (Site 15), 10I (Site 16) and 10J (Site 18). Thetemperature in various depths is labeled with T3-E (surface), T0-B(2-2.5 mm), T1-C (4-5 mm) and T2-D (8-10 mm).

FIG. 11 depicts an ultrasound image of test Site 11 taken 3½ monthsafter exposure. The section below 1105 is outside the cold exposed area;the section below 1106 is within the cold exposed area. The dermis 1102can be clearly distinguished from the fat layer 1103 and the muscularlayer 1104. Within the fat layer 1103 two distinct layers can bedistinguished: the superficial fat layer 1103 a and the deep fat layer1103 b. The ultrasound image matches well with the macroscopic crosssection of the same tissue in FIG. 13C.

FIG. 12 depicts histology of test Site 8 (FIGS. 12A and 12B) six daysafter cold exposure (−7° C., 600 s) and test Site 9, which is anunexposed control (FIGS. 12C and 12D). The micrographs show an image oflow power magnification (1.25×) in FIGS. 12A and 12C and a medium powermagnification (5×) in FIGS. 12B and 12D. The images show the epidermis701, the dermis 702 and the subcutaneous fat 703. While the unexposedcontrol exhibits normal tissue morphology, the cold-exposed tissueexhibits clear signs of panniculitis in the subcutaneous fat.Inflammatory cells have migrated into this area and the average fat cellsize is decreased.

FIGS. 13A-13E depict macroscopic sections through the center ofdifferent test Sites after the pig was sacrificed, 3½ months after coldexposure: 13A (Site 1), 13B (Site 3), FIG. 13C (Site 11), FIG. 13D (Site12) and FIG. 13E (Site 18). Each

Figure exhibits a scale 1300, which has 1 cm units and 1 mm subunits.The epidermis 1301, the dermis 1302, the superficial fat layer 1303 andthe deep fat layer 1304. For the unexposed control FIG. 13B no change ofthickness of different layers can be seen. FIGS. 13A, 13C, 13D and 13Eshow the cross section of cold exposed areas, which is matched to thecentral 4-5 cm of tissue and non-cold exposed areas surround. A decreaseof thickness within the superficial fat layer of the cold exposed areasvs. the non-cold exposed areas can be seen in all cold exposed samples.The change in % of thickness for each of the samples is listed in Table3.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A treatment system for removing heat fromsubcutaneous lipid-rich cells of a region of a subject, comprising: acooling device including a chamber configured to receive target tissueof the region, at least one treatment interface, and at least onethermoelectric cooling element operatively coupled to the at least onetreatment interface and configured reduce a temperature of the regionsuch that lipid-rich cells in the target tissue of the region aredamaged while non-lipid-rich cells in the subject's epidermis and/ordermis are generally not injured; and a suction unit configured to becoupled to the cooling device and to thereafter be activated to draw airfrom the chamber such that the target tissue is pulled into the chamberand into contact with the at least one treatment interface.
 2. Thetreatment system of claim 1 wherein the at least one treatment interfaceis configured to surround the target tissue in the chamber.
 3. Thetreatment system of claim 1 wherein the cooling device is configured tostretch the subject's skin to decrease a thickness of the subject'sepidermis and/or dermis.
 4. The treatment system of claim 1, furthercomprising at least one detector configured to monitor a temperature ofthe at least one treatment interface.
 5. The treatment system of claim 4wherein the at least one thermoelectric cooling element is configured tomaintain an average temperature in a range of about −15° C. to about 5°C.
 6. The treatment system of claim 1, further comprising a temperaturemonitor.
 7. The treatment system of claim 6, further comprising acontrol unit configured to receive temperature information from thetemperature monitor.
 8. The treatment system of claim 1 whereinactivation of the suction unit causes a suction seal to form with thesubject's epidermis around the at least one treatment interface.
 9. Thetreatment system of claim 1 wherein the cooling device is configured tocool both sides of a skin fold in the chamber.
 10. The treatment systemof claim 1 wherein the at least one treatment interface includes acooling plate.
 11. The treatment system of claim 1 wherein the at leastone treatment interface has a curved surface forming a dome.
 12. Thetreatment system of claim 1 wherein the at least one treatment interfacecomprises a material selected from a group consisting of a solid stiffmaterial and a flexible material.
 13. The treatment system of claim 1wherein a surface of the at least one treatment interface comprises atleast one opening connected to the suction unit.
 14. The treatmentsystem of claim 1, further comprising: a detector configured to providetemperature information; and a control unit coupled to the detector andprogrammed to control operation of the cooling device based on thetemperature information from the detector.
 15. The treatment system ofclaim 1 wherein the cooling device is configured to transfer asufficient amount of heat from the subject to cool the lipid-rich cellsto a temperature less than or equal to about 10° C.
 16. The treatmentsystem of claim 1 wherein the cooling device is configured to performone or more cooling cycles and heating cycles.
 17. A treatment systemfor removing heat from subcutaneous lipid-rich cells of a region of asubject, comprising: a cooling device including a chamber, at least onetreatment interface, and at least one cooling element configured toreduce a temperature of the region such that lipid-rich cells in theregion are damaged while non-lipid-rich cells in the subject's epidermisand/or dermis are generally not injured; and a suction unit coupled tothe cooling device and configured to draw air from the chamber such thatthe target tissue is pulled up into contact with the at least onetreatment interface.
 18. The treatment system of claim 17 wherein the atleast one cooling element comprises one or more of a thermoelectriccooling element, a cooling element configured for circulating a coolingagent therethrough, and a conductive cooling element.
 19. The treatmentsystem of claim 17 wherein the cooling device is configured to cool thelipid-rich cells in the region to a temperature less than or equal toabout 10° C.
 20. The treatment system of claim 17, further comprising: adetector configured to provide temperature information; and a controlunit coupled to the detector and programmed to control operation of thecooling device based on the temperature information from the detector.21. A treatment system for removing heat from subcutaneous lipid-richcells of a region of a subject, comprising: a cooling device having achamber for receiving target tissue of the region, at least onetreatment interface, at least one thermoelectric cooling elementoperatively coupled to the at least one treatment interface, and atleast one opening, wherein the cooling device is configured to reduce atemperature of the region such that lipid-rich cells in the targettissue are damaged while non-lipid-rich cells in the subject's epidermisand/or are generally not injured; and a suction unit configured to drawair from the chamber through the at least one opening such that thetarget tissue is pulled into the chamber and into contact with the atleast one treatment interface.
 22. The treatment system of claim 21,further comprising at least one control unit configured to controloperation of the treatment system.
 23. The treatment system of claim 22wherein the at least one control unit is coupled to at least one of thecooling device and the suction unit.
 24. The treatment system of claim22 wherein the at least one control unit includes a power supply thatsupplies power to the cooling device and/or the suction unit.
 25. Atreatment system for removing heat from subcutaneous lipid-rich cells ofa region of a subject, comprising: a cooling device having a chamberconfigured to receive target tissue of the region, at least onetreatment interface, at least one thermoelectric cooling elementoperatively coupled to the at least one treatment interface, and atleast one opening, wherein the cooling device is configured to reduce atemperature of the region in the chamber such that lipid-rich cells inthe target tissue are damaged while non-lipid-rich cells in thesubject's epidermis and/or dermis are generally not injured; a suctionunit configured draw a vacuum to pull the target tissue into the chambertowards the at least one treatment interface; a detector configured toprovide temperature information; and a control unit coupled to thedetector and programmed to control the cooling device based on thetemperature information from the detector.
 26. The treatment system ofclaim 25 wherein the cooling device is configured to cool the lipid-richcells in the region to a temperature less than or equal to about 5° C.27. The treatment system of claim 25 wherein the cooling device isconfigured to perform one or more cooling cycles and heating cycles. 28.The treatment system of claim 25 wherein the cooling device includespassages through which a cooling agent is capable of flowing.
 29. Thetreatment system of claim 25, further comprising a liquid cooling agentflowable through the cooling device and including one or more selectedfrom the group consisting of: saline, glycerol, alcohol, andwater/alcohol mixtures.
 30. The treatment system of claim 25 wherein thedetector includes a thermocouple or a thermistor.